1. Technical Field
The embodiments herein generally relate to mobile television (TV) technologies, and, more particularly, to null symbol detection in data frames transmitted on Digital Audio Broadcasting (DAB), Terrestrial Digital Multimedia Broadcasting (T-DMB), and Digital Audio Broadcasting—Internet Protocol (DAB-IP) mobile TV standards.
2. Description of the Related Art
In the DMB mobile TV standard, each data frame consists of a number of data symbols in addition to a Null symbol and a phase reference symbol. Generally, the Null symbol is an all-zero transmission and it signals the start of the DMB frame. The presence of the Null symbol needs to be detected with great accuracy in order to achieve perfect synchronism with the transmitter and consequently, for the DMB receiver to work properly.
The traditional approach for detecting the presence of the Null symbol is based on detecting the energy of each received symbol. If the energy is below a specific pre-determined threshold, then a Null symbol is declared to be present. The main disadvantage of this approach is that it is not robust to noise and multipath in addition to the fact that the choice of the threshold value tends to require a lot of effort to be optimized for all different scenarios. Accordingly, there remains a need for a new technique for Null symbol detection in digital video data frames.